I changed 6 TRVs this weekend. Re the bit that screws into the body
of the rad, two of them on the old valves had flats that I could get
my wrench onto to get then out, but for the other four I had to insert
a large hex radiator key into the body of the fitting and pound hard
with a mallet to loosen them. As I was doing this I kept imagining
the severe damage I was causing to the body of the rad ...

Touch wood everything seems okay, but was I doing the right thing -
should I have had to resort to brute force, or should I have done
something else a bit more clever? The old valves seemed to have white
putty stuff around the threads.

ANOTHER "did I do the right thing" query from the same job - the
copper thingy inside the compression washers attaching the old valves
to the vertical 15mm inlet pipes were "stuck" (compressed, I supposed)
onto the tops of these pipes. So I cut 3" off each pipe and then
connected an in-line shut-off valve and a short length of new 15m
copper up to the correct height. Again, should I have done this
differently?

I know that asking for advice after the job's over seems silly, but
I've still got another 4 valves to do next weekend.

Thanks

John Forbes